The basic function of a magnetic media follower device is to control the intimate contact between the magnetic head and the magnetic media, such as a photographic film or magnetic tape. To accomplish this there are two primary functional requirements. A load applying member, frequently in the form of a leaf or reed like spring, forces the media against the surface of the head for magnetic reading or writing. The second is the ability for the assembly to track the edge of the media by means of a follower unit so that variations in the cut quality of the media or inaccuracies due to splicing of media do not impact the positioning of the head relative to the edge of the media.
The load applying member may be in the form of a reed like backer or an arched spring which is held in a rigid frame with a cavity designed to hold the spring bent in an arc with opposite legs of the spring captured within the cavity, and the center portion of the spring protruding from an opening to the cavity and bearing on the magnetic media. Known cavity designs with angled walls are inadequate for supporting the spring during engagement with high friction media because the spring tends to conform to the interior cavity shape resulting in functional failure of the spring. Another problem with cavity design is that adequate features are lacking for constraining the spring from rotation about the center hole when high friction media is passed through the interface between the spring and the magnetic head.
A consideration in designing magnetic follower devices for photo finishing equipment which are subject to extensive use and wear is that the component parts such as the arched spring and worn magnetic heads be replaceable without requiring full disassembly of the mechanical unit. In a two-head device it is desirable to have an inventory of critical parts that can be used on either side of the assembly and to minimize parts with left and right hand components
U.S. Pat. No. 2,644,690 discloses a presser and tape guide assembly comprising a symmetrical presser shoe or head mounted on a non-symmetrical body that has differently shaped tape guide wings that engage the tape ahead of and beyond the magnetic head. There is no suggestion that the body is a cover plate or that this construction be used in a two-head device.
U.S. Pat. No. 5,034,836 discloses a magnetic head suspension apparatus for use with photographic film which includes a movable support mounted for movement through an arc having a predetermined radius and a pair of magnetic head suspension assemblies each rotatably mounted on the moveable support. The suspension assemblies are biased towards each other to cause surfaces of the magnetic head assemblies to engage opposite edges of a photographic film respectively. The entire assembly is formed of symmetrical components.
U.S. Pat. No. 5,274,522 discloses a magnetic head-to-media backer device comprising a member adapted to urge a flexible magnetic media into contact with a magnetic head. The rigid frame for holding the member has a cavity and various embodiments of the cavity are described.
U.S. Pat. No. 5,285,324 discloses a magnetic reading and/or recording apparatus which includes a plurality of magnetic reading and/or recording elements to read and/or record information from/on a flexible magnetic recording material, and a flexible plate. A means for arranging the elements and the flexible plate to contact the magnetic recording material with the elements is included, the arranging means includes a pressure pad mounting block having a recess to accept the flexible plate.
U.S. Pat. No. 5,285,325 discloses a two-headed magnetic recording or playback assembly for a camera that includes two symmetrical pressure pad mounting blocks.
It is an objective of this invention to provide a magnetic head-to-media backer device with a cavity designed to prevent functional failure of a spring member.
It is an objective of this invention to provide a magnetic head-to-media backer device with a cavity designed to prevent rotation of a spring member.